As shown in FIG. 3, a conventional basket conveyor comprises a plurality of baskets arranged on a pair of conveyor chains C, C. An article discharging port D formed at the bottom of each basket B may be closed or opened by means of a cover B' which is mounted to a lever S pivotably supported on the basket B by means of a pin P. Said cover B' is urged by its own weight so as to close the port D. A cam lever L attached to said lever S has a cam surface F bent backwardly, which is adapted to be pushed upwardly by a cam roller R which is disposed at the position where the article (not shown) within the basket B is to be discharged. When this engagement of the cam surface F with the cam roller R takes place, the article contained in the basket B may be discharged from the port D as the cover B' is opened against the urging force.
Although the front and rear walls B1, B1 of the basket B spread upwardly as shown in FIG. 5, a pair of the side plates B2,B2 are disposed upright as shown in FIG. 4.
In case of the above-mentioned prior art, such basket conveyors are often arranged at different levels such that article(s) in the basket of an upper basket conveyor may be sorted and discharged into the basket of a lower basket conveyor. The so-called timing basket(s) are adapted to intervene the two basket conveyors arranged at the different levels such that the requisite matching in the timing respecting receipt and discharge of the articles is achieved between the upper and lower basket conveyors. It is possible to accommodate or absorb the timing error to a certain extent in a single stage; however, accommodation of the timing errors in multiple stages is sometimes difficult. As result, the article discharged from the timing basket is sometimes not received properly by the basket of the lower basket conveyor. In order to cope with this, it has been necessary to make the timing basket sized larger than the upper basket; and to make the lower basket sized larger than the timing basket.
This has caused the total number of the baskets mountable to the conveyor chain to decrease, and on the other hand, the basket conveyor has become large sized as a whole requiring a larger mounting space.
In the next place, as shown in FIG. 4, the longitudinal, internal walls B1, B1 of a basket B are conventionally simply flat. Thus, when sheet-like articles are supported upright within the basket B, the lower edges of the articles will be supported on the bottom cover B' and the flat portions of the articles tend to adhere to the flat, internal walls B1, B1. This is oftentimes the case when the humidity is relatively high. Consequently, even if the bottom cover B is opened, the articles may sometimes be prevented from dropping from the basket at the position where they are supposed to be discharged.
Thirdly, as shown in FIG. 4, the edge of the article discharging port D and the upper surface of the bottom cover B' face parallel with each other with a small gap .delta. therebetween. Therefore, in case relatively soft, sheet-like articles, such as, sheets of paper, are held upright in the basket B, with the lower edges of such articles being supported on the upper surface of the bottom cover B', the articles are susceptible to jamming in the small gap as result of the movement of the bottom cover B' when it is opened. This makes the opening motion of the bottom cover B' difficult; and then the discharging of the articles at the prescribed position may not be effected accurately.